http://confocal-microscopy-list.275.s1.nabble.com/Spinning-Disk-Exposure-Times-tp593017p593019.html
time of the camera to a whole number of disk segments. If this is not
(particularly at short exposure times). The UltraVIEW does this by
exposure together. This has to be done accurately, any jitter in the
> Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal
> Thank you Claire for this information. I have reported to Olympus a
> few times, with images, in the past year and a half or so regarding
> disk artifacts. I am happily using their Disk Scanning Unit (DSU) on
> an IX81 frame. Although I rarely get use the spinning disk at such
> low exposures, even with an EM-CCD, I can actually see the
> horizontal and vertical slit appertures that make up the Olympus DSU
> spinning disk. Its made more much more apparent during acquisition
> by exaggerating the image contrast. After acquisition and 3D
> deconvolution, the artifact becomes more robust and very obvious
> when setting thresholds for image segmentation; the disk lines can
> actually be problematic when trying to segment nuclei for example.
> Our disk operates at about 3000rpm, and most of the time its not a
> problem. Shifting the speed to 5000 rpm only made things worse. I do
> not think I have been given notice of a fix as yet.
>
> Cheers
> Farid
>
> On Tue, Apr 29, 2008 at 4:24 PM, Claire Brown
> <
[hidden email]> wrote:
> Search the CONFOCAL archive at
http://listserv.acsu.buffalo.edu/cgi-bin/wa?S1=confocal> Just a note to those of you using spinning disk confocal microscopes.
>
> I have recently been testing out many different spinning disk confocal
> microscopes and one of my worries was artifacts in the images due to
>
> Variable sampling in different pixels due to the spinning nature of
> the
> disk. Most of the commercial companies talk about the importance of
> making
> sure
>
> Your camera and your disk are synchronized. However, what I have
> found using
> a uniform sample (Chroma Technology green fluorescent plastic slide)
> is that
> it is also important to synchronize your exposure time. We found
> with a disk
> spinning at 2500 rpms and an exposure time of 10 ms on an EM-CCD
> camera we
> see lines in the images due to uneven sampling of pixels within the
> image.
> However, if we went with 8, 12 or 16 ms (any multiple of 4 will be
> on the
> same frequency as 2500 rpms or 400 us/spin) these line artifacts
> disappeared
> because our exposure time was in sync with the disk and the camera.
>
>
> These artifacts are not apparent by eye when a heterogeneous
> cellular sample
> is in place because they are very subtle, but they will certainly be
> important for quantitative imaging. So it is very important to use the
> appropriate exposure times.
>
>
> Sincerely,
>
>
> Claire
>
>
>
> _________________________________________________________________
> Claire M. Brown, PhD
> Life Sciences Complex Imaging Facility Director
> McGill University Department of Biochemistry
>
http://www.lifesciencescomplex.mcgill.ca/imaging>
>
>
>
> --
> Farid Jalali MSc
> Senior Research Technician/ Lab Manager
> Dr. Robert Bristow Lab
> Applied Molecular Oncology
> Princess Margaret Hospital
> Toronto, Canada
> 416-946-4501 X4351 (Princess Margaret Hospital)
> 416-581-7754 STTARR at MaRS Building
> 416-581-7791 STTARR Microscopy Suite
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